Starting a business in the UK means making a set of legal and administrative decisions quickly - and in the right order. Get the sequence wrong and you risk trading without proper registration, mixing finances in ways that create tax headaches, or missing an insurance requirement that costs you a client or a claim.
This guide gives you a clear, sequenced business setup checklist built specifically for UK founders - sole traders and new limited company directors alike. Every item is grounded in HMRC rules and UK law. Nothing here is aspirational or optional-if-you-feel-like-it. Each step either protects you legally, keeps you compliant, or prevents a problem that is genuinely hard to fix later.
What You Legally Need to Do Before You Start Trading in the UK
The moment you start trading - that means receiving payment for goods or services, not the moment you register anything - you have legal obligations. Most new founders underestimate how early these kick in.
At a minimum, before or immediately after your first transaction, you need to:
Decide your legal structure - sole trader or limited company
Register with HMRC or Companies House depending on that structure
Understand your record-keeping obligations from day one
Check whether any sector-specific licences or registrations apply to your trade
Sector-specific licences - food hygiene ratings, financial services authorisation, SIA licensing for security - are outside the scope of this guide, but they can be a hard blocker before you trade. Check the GOV.UK licence finder if your sector is regulated.
Trading without registering is not a grey area
If you are self-employed and earning income, HMRC expects you to register. You must register by 5 October in the second tax year of trading at the latest. That deadline is a legal one - but registering immediately when you start is strongly advised. It protects you, simplifies your record-keeping, and removes any ambiguity about when your tax obligations began.
Registering Your Business: Sole Trader or Limited Company
The structure you choose shapes your tax position, your liability, and your administrative burden. Here is what each path involves in practice.
Registering as a Sole Trader with HMRC
As a sole trader, you register for Self Assessment via GOV.UK. HMRC will send you a Unique Taxpayer Reference (UTR) - a 10-digit number that identifies you for tax purposes. You will need this number every time you file a tax return.
Registration takes around 10 working days for your UTR to arrive by post. You can register online at any time via the GOV.UK Self Assessment portal. There is no fee. Do it the week you start trading - do not leave it until the October deadline in your second year.
Incorporating a Limited Company at Companies House
Incorporating online through Companies House typically takes 24 hours and currently costs £100 for the standard online service or £124 for the paper postal service* (no same-day option is available via the GOV.UK web service). You will need a registered office address, at least one director, and a SIC code - a Standard Industrial Classification code that describes your business activity.
* Verify current fees at companieshouse.gov.uk before incorporating, as these figures are subject to change.
Once incorporated, the company is a separate legal entity. You are its director and likely a shareholder. You will need to register the company separately for Corporation Tax with HMRC within three months of starting to trade - Companies House incorporation does not do this automatically.
Contractors: check IR35 before you choose a structure
If you are operating as a contractor providing services to a single client through a limited company, IR35 may affect whether you can draw dividends or must pay PAYE. IR35 is the HMRC legislation that determines whether a contractor should be treated as an employee for tax purposes. It is worth understanding your IR35 position before you set up your company structure - not after your first contract is signed.
Opening a Business Bank Account: Why It Matters Even for Sole Traders
Sole traders are not legally required to hold a separate business bank account. But mixing your personal and business finances from the first transaction creates a record-keeping problem that compounds over time - and makes your Self Assessment return significantly harder to complete accurately.
A separate account lets you see your business income and expenses clearly, makes VAT monitoring straightforward if you approach the threshold, and gives any future accountant or HMRC inspector a clean paper trail.
UK options worth considering for new founders:
Monzo Business (Lite plan) and Starling Business - UK challenger banks with fast digital onboarding and no monthly fees on entry-level accounts; Tide also offers a free entry-level account but charges 20p per UK transfer, and accounting software integrations
HSBC, Barclays, NatWest, Lloyds - traditional high street banks with free banking periods for new businesses, typically 12-24 months
Revolut Business - useful if you trade in multiple currencies or have international clients from the outset
Limited company directors have no choice
If you have incorporated a limited company, a separate business bank account is not optional - it is essential. The company is a separate legal entity and its money is not your money. Mixing company funds with personal funds is a serious accounting and legal problem. Open the account before the company receives any income.
Your Immediate Tax Obligations: Self Assessment, VAT, and Record-Keeping
Tax obligations start the moment you start trading. Not at year end, not when you get around to it - from day one. Here is what you need to understand immediately.
Self Assessment: The Tax Year Timeline
The UK tax year runs from 6 April to 5 April the following year. If you start trading partway through a tax year, your first Self Assessment return will cover the period from when you started trading to the end of that tax year (5 April).
The online filing deadline is 31 January following the end of the tax year. Tax owed is also due on that date. Missing this deadline triggers automatic late-filing penalties from HMRC - they are not discretionary.
VAT: Know the Threshold From Day One
VAT - Value Added Tax - is not something most new founders need to register for immediately. But you must monitor your turnover from the start. The current VAT registration threshold is £90,000 in taxable turnover over any rolling 12-month period. This is not a calendar year - it is any rolling 12 months.
If you exceed this threshold, you must register for VAT within 30 days of the end of the month in which your turnover went over £90,000. Missing this triggers back-dated VAT liability plus penalties. Founders who grow quickly can hit this threshold faster than they expect - which is why tracking cumulative turnover from your first invoice matters, not just at year end.
Record-Keeping: Start as You Mean to Go On
HMRC requires self-employed founders to keep records of all business income and expenses. The legal minimum is five years after the 31 January filing deadline for the relevant tax year. In practice, this means keeping digital or physical copies of invoices, receipts, bank statements, and mileage logs.
A simple spreadsheet works. Accounting software like FreeAgent, Xero, or QuickBooks makes it easier and helps with Making Tax Digital for Income Tax (MTD ITSA) HMRC's digital record-keeping and quarterly reporting regime, which is now mandatory from 6 April 2026 for self-employed people and landlords with qualifying income over £50,000, and will extend to those earning over £30,000 from April 2027 and over £20,000 from April 2028.
Essential Business Insurance: Legal Requirements and Sensible Defaults
Insurance is one of the most misunderstood areas for new founders. Some cover is legally required. Some is not mandated by law but is required by clients or venues before they will work with you. Some is genuinely optional but worth serious consideration. The distinction matters.
Legally Required Insurance
Employers' Liability insurance is a legal requirement for any business that has employees - including part-time, temporary, and some types of casual workers. The minimum cover required is £5 million per claim. Failure to hold valid cover carries daily fines from the Health and Safety Executive. If you are starting as a sole trader with no staff, this does not apply yet - but it applies immediately if and when you take on your first employee.
Commercially Essential Insurance
Public Liability insurance is not legally required for most businesses. But many clients, local authorities, venues, and event organisers will not engage you without it. If you interact with clients, customers, or the public in any capacity - including at your home - Public Liability cover is strongly worth obtaining before your first client engagement.
Professional Indemnity insurance covers claims arising from mistakes, negligence, or professional advice you give that causes a client financial loss. If you provide any form of consultancy, design, legal, financial, technical, or advisory service, most clients will require this. Check your client contracts - many include a minimum indemnity requirement.
Do not assume your home insurance covers business activity
Standard home and contents insurance policies typically exclude business equipment and business visitors. If you are working from home and using your own laptop, camera, tools, or other equipment for business purposes, your personal insurance may not cover a claim. Check your policy wording and consider a dedicated business equipment rider or separate policy.
What Can Wait: Setup Tasks That Do Not Need to Happen Before Your First Invoice
Not every business task is urgent. Part of getting your first 30 days right is knowing what you can defer without consequence - so you focus your time on what genuinely matters first.
The following items are legitimate business tasks, but none of them need to happen before your first invoice leaves your desk:
Trademarking your business name - important if brand protection matters, but not a day-one legal requirement
Building a professional website - useful for credibility, but you can invoice without one
Setting up a pension or business savings product - important for long-term planning, not an immediate compliance task
Registering for ICO (Information Commissioner's Office) data protection if you process only your own customer data in a basic way - check whether registration applies to your specific situation
Formal contracts and terms of business - start drafting these in your first 30 days, but do not let their absence stop you invoicing for work you have genuinely agreed and started
Illustrative example
Illustrative example - based on a common UK founder scenario, not a specific documented case. A freelance designer based in Manchester starts picking up client work in April. She spends her first week building a full website and working on her brand identity - and does not register with HMRC until August, when a client asks for an invoice showing her UTR. HMRC registration takes another 10 working days, delaying her first invoice by two weeks. The setup tasks she treated as urgent were deferrable. The task she deferred was not.
Your First 30 Days at a Glance: The Sequenced Setup Checklist
Use this checklist to work through your business setup in the right order. Items are sequenced by urgency - legally required or financially critical steps come first.
UK Business Setup: First 30 Days
Days 1-3: Legal Structure and Registration
Decide between sole trader and limited company based on your tax position, liability preference, and client requirements. Register with HMRC for Self Assessment (sole trader) or incorporate at Companies House and register for Corporation Tax (limited company). Do not trade before starting this process.
Days 3-7: Business Bank Account
Open a dedicated business bank account before receiving any income. For limited companies this is essential. For sole traders it is strongly recommended to keep finances clean from the first transaction. UK challenger banks (Starling, Monzo, Tide) offer fast digital onboarding. High street banks offer free banking periods - typically 12-24 months.
Days 7-14: Record-Keeping System
Set up a simple system to log income and expenses from the start - spreadsheet or accounting software. Record every transaction. Store digital copies of all invoices and receipts. Note your cumulative turnover from the first invoice to monitor your progress toward the £90,000 VAT threshold.
Days 7-21: Insurance
If you have employees, obtain Employers' Liability insurance before they start work - this is a legal requirement. Obtain Public Liability cover before your first client engagement if you interact with clients or the public. Obtain Professional Indemnity cover if you provide advisory, consultancy, design, or technical services. Check client contracts for minimum cover requirements.
Days 14-30: Contracts, Invoicing, and VAT Awareness
Draft a basic client contract or terms of business - even a short written agreement protects you. Set up a simple invoicing process with a template that includes your name, address, invoice number, payment terms, and (if applicable) UTR or company registration number. Confirm your current cumulative turnover and set a reminder to review it monthly against the VAT threshold.
Before Your First Invoice: Non-Negotiables
HMRC Self Assessment registration completed (sole trader) OR Companies House incorporation and Corporation Tax registration completed (limited company)
Business bank account open and linked to your record-keeping system
Record-keeping system live - every transaction logged from day one
Employers' Liability insurance in place if you have any employees
Public Liability insurance confirmed if working with clients or in public spaces
Professional Indemnity insurance confirmed if your services carry advice or delivery risk
VAT threshold tracking started - note your cumulative turnover from invoice one
Invoice template ready with correct legal information for your structure
The new business setup steps outlined above are not an exhaustive legal guide - but they represent the decisions and registrations that most UK founders need to get right before trading begins. Getting these in place in the right order gives you a clean foundation to build on.
Get Practical Guidance You Can Use This Week
Get Practical Guidance You Can Use This Week
Ready to cut through the noise? Join the BGE newsletter for practical guidance, tool recommendations, and real-world insights for UK founders and business owners - delivered weekly to your inbox. No fluff, no spam, unsubscribe any time.
BGE newsletter
